I put my saddle in storage, expecting it to be unused for about six months. I cleaned it, oiled it, strung up the leathers and stirrups, and covered it with a saddle cover and left it on a saddle rack in my barn so my instructor could keep an eye on it. I'll see how it works out in October I guess.
In after thought, because I was rushing when I did it, I wish I removed my stirrups and leathers. Also, make sure your saddle cover fits the saddle, or it may curl up your flaps.
Use a synthetic oil or oil compound to oil your saddle. Natural oil has fat in it that can cause mold if left unchecked. Waxing (beeswax or some leather wax conditioner) it after cleaning and oiling might help for long term to keep the leather from drying out. You might consider using diluted lemon juice on any moldy spots. I wiped my billets down good with lemon juice before oiling them because they came to me moldy when I bought the saddle.
Still, I would keep an eye on the saddles and check on them every few weeks to make sure the leather does not dry out or mold over. Mold can be as subtle as a filmy layer on the leather, to outright white or green fuzz and will break down the leather. Once that happens, you can't fix it.
And yes, try to store it in a dry place. Humidity is not nice to leather.
Think of it not as a failure but as a success in how not to do it.
Don't look in a horses mouth for a gift.